Thalamus A/P Flashcards
What divides the thalamus into its pieces and what is each sector called?
The Internal Medullary Lamina divides the thalamus into the “Anterior Nuclear group” “Medial Nuclear Group” and a group of ventral nuclei that includes the VA/VL, VPL, VPM, LGB, MGB.
What is the “Ventrobasillary complex?” What does it consist of and what do they do?
Part of the thalamus consisting of the VPL (Ventral Posteriolateral Nucleu) and VPM (Ventral Posteriomedial Nuclei). They are both somatosensory relay nuclei, receiving input and sending it to somatosensory cortex. However, VPL is sensory from the body, trunk and LIMBS (L for limbs) and VPM is sensory from the face and taste.
What is the job of the VA and VL nucleus of the thalamus?
They are motor nuclei and their job is to relay information from Basal Ganglia and the cerebellum up to the motor cortex. Basically they are involved with the planning and execution of movements.
What is the job of the Lateral Geniculate Body (LGB) and Medial Geniculate Body (MGB)?
LGB relays information from the Visual Optic Tract (L for Light) to the primary visual cortex, and the MGB relays information from the auditory from inferior colliculi (M for Music) to the primary auditory cortex.
Generally describe the Anterior and the Medial Nucleus in the thalamus?
They are part of the limbic system and plays some poorly understood role in memory consolidation. AN takes information from the Mammillary nucleus (from the Mammillothalamic tract) to the Cingulate gyrus (part of the papez circuit).
What part of the thalamic nucleus is damaged in Wornicke Korsakoff syndrome?
The MD nucleus. Causes antrograde and retrograde amnesia with confabulations.
What is the function of the nucleus called “Pulvinar?”
It integrates visual and audio input. It’s the largest nucleus in the posterior of the thalamus, and responsible for visual attention, suppression of irrelevant stimuli and utilizing information to initiate eye movements.
What is the function of the midline or intralaminar nuclei?
Functions in sleep/wake cycles and arousal.
What is the most important nucleus of the dorsomedial nucleus?
The medial nucleus, gets input from the amygdala, prefrontal cortex and temporal lobe. Sends output to prefrontal cortex and cingulate gyrus.
What is the input/output of the VA and VL?
VA has input from the globus palladus and substantia nigra, and output to premotor and primary motor cortex. VL has input from Globus Palladus and dentate nucleus from the cerebellum, output to the primary motor cortex (in Brodmann area 4). Output from both VA and VL goes to upper motor neurons in primary motor cortex.
What are the inputs and outputs of the VPL?
Input from somatosensory and nociceptive information ascends the medial lemniscus and ascends the spinothalamic tract. Output is primary somatosensory cortex of parietal lobe.
Inputs and outputs of the VPM?
Input is from ascending trigeminal and taste pathway (gustatory pathway). Output is to primary somatosensory cortex of parietal lobe.
What is the input and output from the medial and lateral geniculate body?
Medial for music, input is auditory information that ascends via the inferior colliculus and output is primary auditory cortex. Lateral is for light, input is from the optic tract and output is geniculocalcarine or visual radiations that project to the primary visual (striate) cortex in occipital lobe.
Input and output from the Midline and intralaminar nuclei?
Input from brain stem reticular formation and spinothalamic tract, interothalamic tract sends pain information to the cingulate gyrus.
What embryologic origin does the thalamus come from? What’s it general job?
It is the largest part of the diencephalon. It is the primary relay station for all pathways except olfaction.
